Abstract: Based on the fact that electrochromic films have important research and development prospects in military camouflage, building energy saving, automobiles and other industrial fields, the surface of La₂O₃ was modified by silane coupling agent KH-550 and compounded with conductive polymer polyaniline (PANI) to prepare f-La₂O₃/PANI electrochromic material. Comparative analysis of composite electrode and pure PANI electrode by XRD, FTIR, SEM-EDS, UV-vis, and electrochemical workstation. The effect of f-La₂O₃ addition on the structure, morphology, electrochemical properties and electrochromic properties of PANI was investigated. The results show that the incorporation of f-La₂O₃ makes the PANI fibers tend to be smaller, and the composite material has higher crystallinity and molecular chain orientation than pure PANI; f-La₂O₃ will break the network cross-linking structure of PANI, resulting in a decrease in the electrochemical performance of the composite, but it can accelerate the transition process of PANI protonation and deprotonation, and effectively inhibit the oxidative degradation of PANI during the electrochromic process of the film; When f-La₂O₃/aniline molar ratio is 1∶3.5, the electrochromic performance of f-La₂O₃/PANI composite reaches the best, the coloration efficiency (CE) at 570 nm is 22.81 cm²·C⁻¹, and the fading and coloring response time (τ_b, τ_c) are 1.29 s and 1.33 s, respectively. After 320 cycles of fading, the electrochemical activity of the thin films remains about 50% of the initial value.